Drawing continuous sheet glass



J. C. HENDERSON DRAWING CONTINUOUS SHEET (HJASISv New. 12, 1929.

Filed Oct. 50, 1926 Patented Nov. l2, 1929 JOHN G. HENDERSON, OF NEW YORK, N. Yd, ASSIGNOR TO LIBBEY-OWENS GLASS COINCPANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO DRAWING CONTINUOUS SHEET GLASS Application filed October 30, 1926. Serial No. 145,860.

This invention relates to the art of drawing a continuous sheet of glass, and more particularly to an improved method and apparatus for bending the plastic glass sheet from one plane to another without injuring the surfaces thereof.

In certain well-known systems for producing sheet glass, forexample the Colburn process as set forth in the Colburn Patent,

1,248,809, granted December 4, 1917, the

glass sheet is drawn upwardly from a pool of molten glass and then, while partially set but still somewhat plastic, is bent through approximately 90 into the horizontal plane where it is carried away through suitable drawing and flattening mechanism into a leer.- While being bent from the vertical to the horizontal plane the sheet is supported upon some form of bending member, usually a highly polished metal roller. It is essential that the cylindrical sheet-supporting surface of-this roller be absolutely smooth, clean, and maintained at just the proper temperature, else the delicate fire-polished surface of the plastic sheet will be injured while passin over the roller.

In order to avoid the difliculties incident to the use of such a bending member, the present system has been devised. The plastic sheet. after becoming partially set, is gripped adjacent its edges, and supported upon, suitable members which move with the sheet during its bending operation. A. pair of rather large metal discs or wheels may be used, which are so mounted. that their sheet-edge carrying surfaces diverge from one another as they move with the sheet so that a constant- 1y increasing lateral tension is applied to the glass sheet throughout the bending operation. This lateral tension will tend to prevent sagging of the unsupported main central portion of the sheet, which is carried from the vertical into the horizontal plane without contacting with any solid bodies which might otherwise injure the delicate fire-polished surface of the sheet.

The invention forming the particular subject-matter of the present application is an improvement or addition 'to the apparatus above described, whereby the otherwise un- I supported central portion of the sheet is carried, during the bending operation, upon a blanket of air under pressure. .More specifically, a casing, substantially enclosed except for that face adjacent the glass sheet, is

mounted beneath the bending arc of the sheet, and compressed air is forced therein, and im 'pelled toward the sheet surface and in the following detailed description of one approved form of the apparatus embodying the principles of this invention.

In the accompanying drawings:

Fig. 1 is an elevation of the main features of the apparatus, the right hand portion of the figure being broken away to show part of the apparatus in transverse verticalsection.

-Fig. 2 is a longitudinal vertical section, taken substantially on the line 2''-2 of Fig.1.

The glass sheet 1 is first drawn upwardly so from any suitable molten source, and, after being bent into the horizontal plane as hereinafter described, is carried away through any suitable form of drawin and flattening mechanism into the leer. T e edges of the sheet, during the bending operation, are gripped and supported by a pair of metallic wheels or discs 2 having roughened or grooved sheet-supporting peripheries 3. The axes 4 of these discs are so inclined that the sheet engaging portions of the peripheries of c the discs diverge from one another as they move forwardly and upwardly with the glass sheet. In this way a continuous lateral tension is appliedtothe plastic glass sheet during its entire arc of travel during the bending operation.

Mounted beneath the bending arc of the glass sheet is a stationary hollow metallic casing 5, having a diameter substantially as large as that of the sheet carrying portions of discs I 2. This casing is closed atits ends and for three-quarters of its cylindrical surface, but

the 90 arc of its cylindrical surface directly underlying the bending portion of the glass porting brackets 6, as indicated by the arrows in Figs. 1 and 2.

.Rotatably mounted within, and rather closely fitting the interior of, the casing 5, is a fan member 7, here shown as supported by roller bearings 8 in the opposite ends of the casing. This fan 7 is provided with a series of substantially radial blades or vanes 9,

which may be curved backwardly somewhatwith respect to their direction of rotation,

as indicated by the arrow, Fig. 2, so as to increase their tendency 'to throw the air outward toward the surface of the glass sheet 1. The fan 7 is driven from a shaft 10 through worm gearing 11 connected with one end 12 of the supporting axle for the fan.

When this fan is driven in the direction of the arrow, Fig. 2, the air, which is being forced into the casing 5, will be impelled outwardly toward the bending glass sheet which directlyoverlies the open side of the casing,

and will also be impelled to travel in the same direction as the glass sheet, as indicated b the chain of small arrows at the upper le t hand side of Fig. 2. This'will create a constantly renewed blanket of air under pressure beneath the sheet 1 and at -least partially counteract the natural tendency of the unsupported sheet to sag under the influence of gravity. This current of air moving beneath and in the same direction as the sheet will also assist, to some extent, in carrying the sheet forwardly and upwardly around the arc of its bending travel. At the same time this portion of the sheet is untouched by any solid bodies and there is no opportunity for injury tpl the delicate fire-polished surface of the s ect.

It is to be understood that the form ofothe invention herewith shown and described is to be taken as the preferred embodiment of the same, and that various changes in the shape, size and arrangement of parts may be resorted to withoutdeparting from the s irit of the invention or the scope of the subjolned claims.

Claims 1. That improvement in the art of drawing sheet glass, which consists in supporting a portion of the moving sheet while being bent from one plane into another upon a blanket of air which is mechanically moved with the s ieet.

ing sheet glass, which consists in bending the sheet from one plane into another by supporting the edge portions of the sheet upon members traveling with the sheet, and supporting the central portion of the sheet upon a blanket of air under pressure, which is mechanically moved in the direction of travel of the sheet.

3. That improvement in the art of drawing sheet glass, which consists in bending the sheet from one plane into another by supporting the edge portions of the sheet upon members traveling with the sheet, simultaneously stretching the sheet laterally, and

supporting the central portion of the sheet upon a blanket of air under pressure.

4. In a sheet glass drawing apparatus, means for supporting a portion of the glass sheet out of contact with any solid bodies, comprising a casing closed except" for that face adjacent the sheet surface, means for forcing air under pressure into the casing, and moving means within the casing for forcing the air toward the sheet surface.

5. In a sheet glass drawing apparatus, means for supporting a portion of the glass sheet out of contact with any solid bodies, comprising a casing closed except for that face adjacent the sheet surface, means for forcing air under pressure into the casing, and moving means within the casipg for forcing the air toward the sheet surface, and in the direction of travel of the sheet.

6. In a sheet glass drawing apparatus, means for supporting the glass sheet while'it 2. That improvement in the art of drawis being bent from one plane into another,

comprising a stationary casing mounted within the bending arc of the sheet, the casing being closed except for the face adjacent the inner surface of the bending sheet, means for forcing air under pressure into the casing, and moving means Within the casig for forcin the air toward the sheet surface.

I. In a sheet glass drawing apparatus, means for supporting the glass sheet while it is being bent from one plane into'another, comprising a stationary casing mounted within the bending arc of the sheet, the casing inner surface of the bending sheet, and a rotary member Within the casing, having a series of substantially radial vanes for forclng the air within the casing toward the sheet surface, and in the direction of travel of the sheet.

9. in a sheet glass drawing apparatus, means "for supporting the glass sheet while it is being bent from one plane into another, comprising members supporting and moving with each sheet edge, and a stationary casing mounted between these members within the bending are of the sheet, the casing being closed except for the face adjacent the inner surface of the glass sheet, and moving means within the casing for forcing the air toward the sheet surface and in the direction of travel of the glass sheet.

10. In a sheet glass drawing apparatus, means for supporting the glass sheet while it is being bent from one plane into another, comprising members supporting and moving with each sheet edge, and a stationary casing mounted between these members within the bending arc of the sheet, the casing being closed except for the face adjacent the inner surfaces of the glass sheet, and a rotary member within the casing having a series of substantially radial vanes for forcing the' air' within the casing toward the sheet surface and in the direction of travel thereof.

11. In sheet glass drawing apparatus,

r means for supporting the glass sheet while it is being bent from one plane into another including a rotatable member arranged at each edge of the sheet and about which the sheet may be deflected, the main body part of the sheet lying between the edge contacting means being out of contact with any solid bodies, and a rotatable member positioned between the edge contacting members about which the sheet is deflected for creating an air cushion for supporting the body portion of thesheet, the said rotatable member being operated in a manner to cause the cushion of air to travel with the sheet. a

12. In sheet glass drawing apparatus, means for supporting the glass sheet while it is being bent from one plane into another, including a rotatable member arranged at each edge of the sheet and about which the sheet may be deflected, the main body part of the sheet lying between the edge contacting means being out of contact with any solid bodies, and a rotatable fan positioned between the edge contacting members about which the sheet is deflected for creating an air cushion for supporting the body portion of the sheet, the said rotatable fan being operated in a manner to cause the cushion of air to travel with the sheet.

13. In a sheet glass drawing apparatus, means for supporting the glass sheet while it is being bent from one plane to another, including a rotatable fan member mounted within the bending arc of the sheet operated in a manner to create an air cushion for supporting the main body part of the sheet, said I 

